[Python-Dev] troubling math bug under IRIX 6.5
Flying Cougar Burnette
tommy@ilm.com
Tue, 13 Feb 2001 17:57:03 -0800 (PST)
Tim Peters writes:
|
| > now neither does. shall I turn opts back on and try a few more
| > cases?
|
| Yes, please, one more:
|
| 4.0 * 3.1
|
| Or, if that works, go back to the failing
|
| 4.0 * math.exp(-0.5)
both of these work, but changing the 4.0 to an integer 4 produces the
bus error. so it is definitely a conversion to double/float thats
the problem.
|
| In any failing case, can you jump into a debubber and get a stack trace?
sure. I've included an entire dbx session at the end of this mail.
|
| Do you happen to have
|
| WANT_SIGFPE_HANDLER
|
| #define'd when you compile Python on this platform? If so, it complicates
| the code a lot. I wonder about that because you got a "bus error", and when
| WANT_SIGFPE_HANDLER is #defined we get a whole pile of ugly setjmp/longjmp
| code that doesn't show up on my box.
a peek at config.h shows the WANT_SIGFPE_HANDLER define commented
out. should I turn it on and see what happens?
|
| Another tack, as a temporary workaround: try disabling optimization only
| for Objects/floatobject.c. That will probably fix the problem, and if so
| that's enough of a workaround to get you unstuck while pursuing these other
| irritations.
this one works just fine. workarounds aren't a problem for me right
now since I'm in no hurry to get this version in use here. I'm just
trying to help debug this version for irix users in general.
------------%< snip %<----------------------%< snip %<------------
(tommy@mace)/u0/tommy/pycvs/python/dist/src$ dbx python
dbx version 7.3 65959_Jul11 patchSG0003841 Jul 11 2000 02:29:30
Executable /usr/u0/tommy/pycvs/python/dist/src/python
(dbx) run
Process 563746 (python) started
Python 2.1a2 (#6, Feb 13 2001, 17:43:32) [C] on irix6
Type "copyright", "credits" or "license" for more information.
>>> 3 * 4.0
12.0
>>> import math
>>> 4 * math.exp(-.5)
Process 563746 (python) stopped on signal SIGBUS: Bus error (default) at [float_mul:383 +0x4,0x1004c158]
383 CONVERT_TO_DOUBLE(v, a);
(dbx) l
>* 383 CONVERT_TO_DOUBLE(v, a);
384 CONVERT_TO_DOUBLE(w, b);
385 PyFPE_START_PROTECT("multiply", return 0)
386 a = a * b;
387 PyFPE_END_PROTECT(a)
388 return PyFloat_FromDouble(a);
389 }
390
391 static PyObject *
392 float_div(PyObject *v, PyObject *w)
(dbx) t
> 0 float_mul(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/floatobject.c":383, 0x1004c158]
1 binary_op1(0x100b69fc, 0x10116788, 0x0, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/abstract.c":337, 0x1003ac5c]
2 binary_op(0x100b69fc, 0x10116788, 0x8, 0x0, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/abstract.c":373, 0x1003ae70]
3 PyNumber_Multiply(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/abstract.c":544, 0x1003b5a4]
4 eval_code2(0x1012c688, 0x0, 0xffffffec, 0x0, 0x0, 0x0, 0x0, 0x0) ["/usr/u0/tommy/pycvs/python/dist/src/Python/ceval.c":896, 0x10034a54]
5 PyEval_EvalCode(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/ceval.c":336, 0x10031768]
6 run_node(0x100f88c0, 0x10116788, 0x0, 0x0, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":931, 0x10040444]
7 PyRun_InteractiveOne(0x0, 0x100b1878, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":540, 0x1003f1f0]
8 PyRun_InteractiveLoop(0xfb4a398, 0x100b1878, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":486, 0x1003ef84]
9 PyRun_AnyFileEx(0xfb4a398, 0x100b1878, 0x0, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":461, 0x1003eeac]
10 Py_Main(0x1, 0x0, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Modules/main.c":292, 0x1000bba4]
11 main(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Modules/python.c":10, 0x1000b7bc]
More (n if no)?y
12 __start() ["/xlv55/kudzu-apr12/work/irix/lib/libc/libc_n32_M4/csu/crt1text.s":177, 0x1000b558]
(dbx)